Intermediate transfer belts can be generated in the form of seamed belts fabricated by fastening two ends of a web material together, such as by welding, sewing, wiring, stapling, or gluing, and such belts can also be generated in the form of a seamless intermediate transfer belt.
More specifically, seamed belts can be fabricated from a sheet cut from an imaging member web. The sheets are generally rectangular or in the shape of a parallelogram where the seam does not form a right angle to the parallel sides of the sheet. All edges may be of the same length or one pair of parallel edges may be longer than the other pair of parallel edges. The sheets are formed into a belt by joining overlapping opposite marginal end regions of the sheet. A seam is typically produced in the overlapping marginal end regions at the point of joining where the joining may be effected by any suitable means. Typical joining techniques include welding, such as ultrasonic welding, gluing, taping, pressure heat fusing, and the like.
An ultrasonic welding process is accomplished by retaining in a down position the overlapped ends of a flexible imaging member sheet with a vacuum against a flat anvil surface, and guiding the flat end of an ultrasonic vibrating horn transversely across the width of the sheet, over and along the length of the overlapped ends, to form a welded seam. Ultrasonically welding results in an overlap seam that has an irregular surface topology rendering it difficult for a cleaner blade to clean toner around the seam, and which irregular surface can also cause damage to the cleaner blades by nicking the cleaning edge of the blade. In addition, toner trapping resulting from the poor cleaning and the blade damage causes streaking from the seam, which in turn adversely impacts image quality.
When ultrasonically welded into a belt, the seam of multilayered electrophotographic imaging flexible member belt may occasionally contain undesirable high protrusions such as peaks, ridges, spikes, and mounds. These seam protrusions present problems during image cycling of the belt machine because they interact with cleaning blades to cause blade wear and tear, which ultimately adversely affect cleaning blade efficiency, and reduce service life.
A bump, surface irregularity, or other discontinuity on the surface of the belt and in the seam of the belt may disturb the tuck of the cleaning blade as it contacts the intermediate transfer belt surface to effect residual toner and debris removal. The increased height differential may allow toner to pass under the cleaning blade and not be cleaned. Moreover, seams with a bump or other morphological defects can cause the untransferred residual toner to be trapped in the sites of seam surface irregularities. The seam of an intermediate transfer belt, which is repeatedly subjected to the striking action by a cleaning blade under machine functioning conditions, has triggered the development of premature seam delamination failure. In addition, the discontinuity in belt thickness due to the presence of an excessive seam height yields variances of mechanical strength in the belt and reduces the fatigue flex life of the seam when cycling over the belt module support rollers. As a result, both the cleaning life of the blade and the overall service life of the intermediate transfer belt can be diminished.
Also, such irregularities in the belt height and the seam height emit vibrational noise in xerographic development systems, which noise disturbs the toner image on the belt, and degrades resolution and transfer of the toner image to the final copy sheet. This is particularly prevalent in those applications requiring the application of multiple color layers of liquid or dry developer on an intermediate transfer belt, which are subsequently transferred to a final copy sheet. Further, the seam discontinuity or bump in such a belt may result in inaccurate image registration during development, inaccurate belt tracking, and overall deterioration of motion quality, as a result of the translating vibrations.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member or photoconductor. The latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles and colorant, which are commonly referred to as toner. Generally, the electrostatic latent image is developed by contacting the latent image with a developer mixture comprised of carrier granules having toner particles adhering triboelectrically thereto, or there can be selected for development a liquid developer material, which may include a liquid carrier with toner particles, dispersed therein. The developer material is advanced into contact with the electrostatic latent image, and the toner particles are deposited thereon in image configuration. Subsequently, the developed image is transferred to a copy sheet. It is advantageous in some situations to transfer the developed image to a coated intermediate transfer web, belt or component, and subsequently transfer with high transfer efficiency the developed image from the intermediate transfer member to a permanent substrate. The toner image is subsequently usually fixed or fused upon a support, which may be the photoconductor or other support such as plain paper.
In electrostatographic printing machines wherein the toner image is electrostatically transferred by a potential difference between the imaging member and the intermediate transfer member, the transfer of the toner particles to the intermediate transfer member and the retention thereof should be substantially complete so that the image ultimately transferred to the image receiving substrate will have a high resolution. Substantially about 100 percent toner transfer occurs when most or all of the toner particles comprising the image are transferred, and little residual toner remains on the surface from which the image was transferred.
Intermediate transfer members may allow for a number of positive attributes, such as enabling high throughput at modest process speeds, improving registration of the final color toner image in color systems using synchronous development of one or more component colors using one or more transfer stations, and increasing the range of final substrates that can be used.
In operation, an intermediate transfer belt is brought into contact with a toner image-bearing member such as a photoreceptor belt. In the contact zone, an electrostatic field generating device, such as a corotron, a bias transfer roller, a bias blade, or the like, creates electrostatic fields that transfer toner onto the intermediate transfer belt. Subsequently, the intermediate transfer belt is brought into contact with a receiver. A similar electrostatic field generating device then transfers toner from the intermediate transfer belt to the receiver. Depending on the system, a receiver can be another intermediate transfer member or a substrate onto which the toner will eventually be fixed. In either situation, the control of the electrostatic fields in and near the transfer zone is a significant factor in toner transfer.
Thus, there is a need for a seamed member, such as a belt that avoids or eliminates a number of the above disadvantages, and more specifically, there is a need for an ITB with excellent surface topology such that it can withstand dynamic fatigue conditions. For example, the acrylic resin coated belt as disclosed herein provides a smoother belt surface with substantially decreased or eliminated profile protrusions or irregularities thereby extending its service life. Also, there is a need for a substantially completely imageable member which avoids or minimizes a number of the disadvantages indicated herein by overcoating the entire member including the seam, with an acrylic resin that is crosslinked, and which layer is mechanically robust, and electrically is about equal to the surface resistivity of the seamed intermediate transfer belt (ITB).